#pragma once
#include<iostream>
#include<vector>
#include<string>

using namespace std;

template<class K>
struct DefaultHashFunc
{
	size_t operator()(const K& key)
	{
		return (size_t)key;
	}
};

template<>
struct DefaultHashFunc<string>
{
	size_t operator()(const string& str)
	{
		// BKDR
		size_t hash = 0;
		for (auto ch : str)
		{
			hash *= 131;
			hash += ch;
		}

		return hash;
	}
};



namespace open_hash
{
enum STATE
{
	EXIST,
	EMPTY,
	DELETE
};
template<class K,class V>
struct HashData
{
	pair<K, V> _kv;
	STATE _state = EMPTY;
};

template<class K, class V,class HashFunc=DefaultHashFunc<K>>
class HashTable
{
public:
	HashTable()
	{
		_table.resize(10);
	}

	bool Insert(const pair<K, V>& kv)
	{
		if (Find(kv.first))
		{
			return false;
		}

		//检查负载因子
		if (_n * 10 / _table.size() >= 7)
		{
			int newsize = _table.size() * 2;
			HashTable newtable;
			newtable._table.resize(newsize);
			//把旧表的数据插入到新表
			for (int i = 0; i < _table.size(); i++)
			{
				if (_table[i]._state == EXIST)
				{
					newtable.Insert(_table[i]._kv);
				}
			}

			//交换两个表
			_table.swap(newtable._table);

		}
		HashFunc hf;
		size_t hashi = hf(kv.first) % _table.size();
		//线性探测
		if (_table[hashi]._state == EXIST)
		{
			hashi++;
			hashi %= _table.size();
		}

		_table[hashi]._kv = kv;
		_table[hashi]._state = EXIST;
		_n++;
		return true;
	}

	HashData<const K, V>* Find(const K& key)
	{
		HashFunc hf;
		size_t hashi = hf(key) % _table.size();
		//线性探测
		while (_table[hashi]._state != EMPTY)
		{
			if (_table[hashi]._state == EXIST && _table[hashi]._kv.first == key)
			{
				return (HashData<const K, V>*) & _table[hashi];
			}
			hashi++;
			hashi %= _table.size();
		}

		return nullptr;
		
	}

	bool Erase(const K& key)
	{
		auto ret = Find(key);
		if (ret)
		{
			ret->_state = DELETE;
			_n--;
			return true;
		}
		return false;
		
	}
private:
	vector<HashData<K,V>> _table;
	size_t _n = 0;  //有效数据的个数
};
}

namespace hash_bucket
{
	template<class K, class V>
	struct HashNode
	{
		pair<K, V> _kv;
		HashNode* _next;

		HashNode(const pair<K, V>& kv)
			:_kv(kv)
			, _next(nullptr)
		{}
	};

	template<class K, class V, class HashFunc = DefaultHashFunc<K>>
	class HashTable
	{
	public:
		typedef HashNode<K, V> Node;

		HashTable()
		{
			_table.resize(10, nullptr);
		}

		~HashTable()
		{
			for (size_t i = 0; i < _table.size(); i++)
			{
				Node* cur = _table[i];
				while (cur)
				{
					Node* next = cur->_next;
					delete cur;
					cur = next;
				}
				_table[i] = nullptr;

			}
		}


		bool Insert(const pair<K, V>& kv)
		{
			if (Find(kv.first))
			{
				return false;
			}

			HashFunc ht;

			//负载因子为1就扩容
			if (_n == _table.size())
			{
				size_t newsize = _table.size() * 2;
				//创建新表
				vector<Node*> newtable;
				newtable.resize(newsize, nullptr);

				//遍历旧表，顺手牵羊，插入到新表
				for (int i = 0; i < _table.size(); i++)
				{
					Node* cur = _table[i];
					while (cur)
					{
						size_t hashi = ht(cur->_kv.first) % newtable.size();
						Node* next = cur->_next;
						cur->_next = newtable[hashi];
						newtable[hashi] = cur;
						cur = next;
					}
					_table[i] = nullptr;
				}

				//交换新旧表
				_table.swap(newtable);
			}

			size_t hashi = ht(kv.first) % _table.size();
			//头插
			Node* newnode = new Node(kv);
			newnode->_next = _table[hashi];
			_table[hashi] = newnode;
			_n++;
			return true;

		}

		Node* Find(const K & key)
		{
			HashFunc ht;

			size_t hashi = ht(key) % _table.size();
			Node* cur = _table[hashi];
			while (cur)
			{
				if (cur->_kv.first == key)
				{
					return cur;
				}

				cur = cur->_next;
			}

			return nullptr;
		}

		bool Erase(const K& key)
		{
			HashFunc ht;

			size_t hashi = ht(key) % _table.size();
			Node* cur = _table[hashi];
			Node* prev = nullptr;

			while (cur)
			{
				if (cur->_kv.first == key)
				{
					if (prev == nullptr)
					{
						_table[hashi] = cur->_next;
					}
					else
					{
						prev->_next = cur->_next;
					}
					delete cur;
					return true;
				}

				prev = cur;
				cur = cur->_next;
			}

			return false;
		}

		void Print()
		{
			for (int i = 0; i < _table.size(); i++)
			{
		    	Node* cur = _table[i];
				printf("[%d]:", i);
				while (cur)
				{
					cout << cur->_kv.first << ":" << cur->_kv.second << "->";
					cur = cur->_next;
				}
				printf("NULL\n");
			}
		}
		private:
			vector<Node*> _table;
			size_t _n = 0;
		};
}